Age-related sarcopenia in humans is associated with reduced synthetic rates of specific muscle proteins.
Sarcopenia of aging is not explained entirely on the basis of age-associated reduced physical activity. Progressive neuromuscular changes and diminishing anabolic hormone levels are thought to contribute to the pathogenesis of sarcopenia. Decline in muscle mass indicates a decline in muscle protein content. Recent studies demonstrated an age-related decline in synthesis rate of mixed muscle proteins, myosin heavy chain and mitochondrial protein. Reductions in myosin heavy chain and mitochondrial protein synthesis rates have been correlated with age-associated decrements in muscle strength and aerobic exercise tolerance, respectively. These changes have been reported as early as 50 y of age and are related to the decline in insulin-like growth factor (IGF)-I, testosterone and dehydroepiandrosterone (DHEA)-sulfate. The declining ability to remodel these important muscle proteins may therefore play a role in the development of muscle wasting, metabolic abnormalities and impaired physical functioning seen in old age.
Proctor
D N
DN
Endocrine Research Unit, Mayo Clinic and Foundation, Rochester, MN 55905, USA.
Balagopal
P
P
Nair
K S
KS
D000375:Aging / Q000097:blood / Q000378:metabolism*; D005260:Female; D006728:Hormones / Q000378:metabolism; D006801:Humans; D008297:Male; D008928:Mitochondria / Q000201:enzymology / Q000378:metabolism*; D009124:Muscle Proteins / Q000096:biosynthesis* / Q000378:metabolism; D009133:Muscular Atrophy / Q000209:etiology* / Q000378:metabolism; D011506:Proteins / Q000378:metabolism
D006728:Hormones; D009124:Muscle Proteins; D011506:Proteins